Kennedy, the daughter of the late Sen. Robert Kennedy, swerved her car into a tractor-trailer on a New York interstate highway in 2012, and tests later found a small amount of sleeping medication in her blood.

Kennedy said on the stand during the trial that she believes she accidentally took the sleeping pill instead of her daily thyroid medication. Both were set out on the counter, in similar bottles, in preparation for an upcoming overseas trip.

Prosecutors argued that she should have pulled over once she realized something was wrong. Her lawyers said, and Kerry testified, that she never realized she was impaired until after the crash.

Her sister, Rory, was a character witness for the defense, and her mother, Ethel Kennedy, was in the courtroom for the trial.